The Perfect Lanyard
A lot of people throw lanyards on their knives and flashlights. They aid in retrieval and are an easy way to customize gear.
The most common lanyard material these days is paracord. There are plenty of weaves and knots that can be used to create a lanyard. The trick is finding exactly what length is best.
I recently wrestled with this question. I wanted a simple lanyard to aid in retrieval of my primary knife. I planned to use a lanyard knot and a simple lark's head knot to attach the lanyard. Initially, I tied on the lanyard knot at an aesthetically pleasing length.
After using the lanyard for a few days I began to realize that it wasn't performing as well as I had desired. When I gripped the lanyard and pulled, allowing the knot to catch between my folded pinky and palm, I was presented with a problem: the handle of the knife was too far away. Sure, I could pull the knife from my pocket, but there was a second movement required - namely grabbing at the handle - to actually use the knife. I realized that the knot had to be closer to the body of the knife. Then, of course, the question of "how close" arose.
The perfect lanyard, I think, is measured by pinching the top of the object as if you're retrieving it from your pocket and measuring the distance from its end to the bottom of your hand. Essentially, the width of your middle, ring, and pinky fingers.
This length ensures that the knot catches the exterior of my closed palm when retrieving the knife. Anything shorter and it wouldn't be as convenient and anything longer would result in the problems described above.
Of course, depending on where you're carrying the object and how you're planning to retrieve it matters. For retrieval from a clipped position in a pocket, this method seems to work quite well.
Other lengths may work just as well, of course. This just so happens to be the one way I measured the length of mine. Another option could be tying the knot such that it lands between any other two fingers, a method that could work equally well as the one I'm currently employing.
Ultimately, whatever design works is the design that should stay. There are some designs that work better than others, though; this just might be one of them.